Beer
alcohol beer beer !! Malting Lightly crush (ie NOT to a powder) the malted grains in a mill, or mortar and pestle. !! Mashing rel://files/beer-enzymes.png | 35-45 C | beta-glucanase, debranching enzymes | solubilises starches | 45-55 C | proteolytic enzymes | breaks up large proteins | 55-65 C | beta-amylase | produces maltose | 68-72 C | alpha-amylase | produces maltose + other sugars !! Sparging The milled grains are exposed to hot water in order to extract sugars. The sugars are liberated by the actions of enzymes in the grains, which act on starches. Then the water is removed from the mixture, carrying the sugars away with it. The hydrated, activated grain mixture is called the *mash*. The liquid that is drained off the mash is called the *wort*. Rinsing the mash, to extract further sugars after the mash is drained, is called *sparging*. The container where lautering takes place is called the *mash tun* or *lauter tun*. !!! Fly sparging Commonest method. Hot water is continually sprayed onto the mash, to replace the wort which is continually draining from the bottom. !!! "No-sparge" sparging Very inefficient. !!! Batch sparging A set quantity of hot water is added to the mash in a container. Then all the liquid is drained off. Advantage: much quicker (20 min versus 90 min+), much easier. Disadvantage: less efficient extraction than fly sparging. Compensate by using ~ 10% more grains. !!!! Equipment Mash tun Boiling kettle 1L jug !!!! Calculations !!!!= Strike temperature (Tstrike) Tstrike = 0.4/ratio * (Tmash - Troom) + Tmash Where: ratio = desired ratio of water to grain in mash, in qt/lb, usually 1-1.3 Tmash = desired mash temperature, usually 65-68C Troom = room temperature Eg: Room tep 24C, desired mash temp 68C, ratio 1.2 Tstrike = 0.4/1.2 * (68 - 24) + 68 = 0.333 * 44 + 68 = 82 C !!!!= Strike volume (Vstrike) This depends on the recipe and the amount of grain you are using. Water is usually added in a particular *ratio* to the weight of grain. The ratio may be specified by the recipe. It is usually 1-1.3 qt/lb, or 2.2-2.9 L/kg. | Qt/lb | L/kg | 1.0 | 2.25 | 1.1 | 2.48 | 1.2 | 2.7 | 1.3 | 2.93 | 1.4 | 3.15 | 1.5 | 3.38 | x | 0.95 * x / 0.422 So if using a ratio of 1.2 qt/lb (2.7 L/kg) and 5kg of grain, Vstrike would be 2.7 * 5 = 13.5L. !!!!= Water volume Fermentable volume (Vf) is less than pre-boil volume (Vp), because of evaporation during boiling. The amount of volume lost depends on the dimensions of the boiler etc. About 1/4 is a reasonable rule of thumb, for a 60min boil. So for Vf of 4L, need Vp of 5.3L. For Vf of 22L, need Vp of 29.3L. Vp = Vf / 0.75 We will collect this pre-boil volume by sparging in the tun, in several batches (at least 2). Assuming we are doing 2 sparges, we therefore want to collect 0.5 * Vp from each runoff. In the first runoff, some of the liquid will come from the *strike water* we added to start the mash an hour ago. However the grains will absorb about their weight in water (1L/kg), so some of the strike water will be retained by the grains and will not be recoverable. So for the *first* runoff, we will need to add some "top-up" water (Vx) just before starting. Vx = 1/2 * Vp - (Vstrike - W - DS) Where: Vx = the amount of top up water we will need to add Vp = the desired total pre-boil wort volume (note the 1/2 multiplier assumes 2 runoffs) Vstrike = the volume of water added at the beginning of mashing W = the weight of the dry grain DS = the "dead space" in the tun (volume that lies below the outflow hole) For each subsequent runoff, the amount of water to add (Vs) is just equal to 1/2 * Vp (or 1/3 * Vp if doing 3 sparges etc). !!!!= An example To make 23L of fermentable wort, using 5kg grain with a mash water:grain ratio of 1.2 qt/lb (2.7 L/kg), a single mash rest of 68C for one hour, and batch sparging with 2 runoffs. Vf = 23 L W = 5 kg ratio = 2.7 L/kg Troom = 24C DS = 300mL = 0.3L Vp = 23 / 0.75 = 31 (round up) Tstrike = 0.4/ratio * (Tmash - Troom) + Tmash = 0.4/1.2 * (68 - 24) + 68 = 82C (note use of *qt/lb* ratio) Vstrike = W * ratio = 5 * 2.7 = 13.5 L Vx (top-up prior to 1st runoff) = 1/2 * Vp - (Vstrike - W - DS) = 1/2 * 31 - (13.5 - 5 - 0.3) = 7.3 L Vs (volume added for second runoff) = 1/2 * Vp = 15.5 L !! Method !!! Equipment Sterilise: - Fermenter, airlock - Boiling kettle - Tun, jug, stirrer, plastic lid (to pour onto during vorlauf) - Hydrometer !!! Mashing On the stove, heat the water (Vp + W + DS + fudge factor) to the desired strike temperature (Tstrike). Preheat the tun by putting some hot water in, then discarding. Add Vstrike. Put milled grains in the tun. Check that we have achieved the desired mash temperature -- if not, add hot or cold water. Stir the grain bed thoroughly but gently, avoiding foaming. Rest for 60 mins, stirring gently every 15-20 min and checking that the temperature stays within about 3C of the mash target. Make sure the water on the stove is back up to Tstrike before proceeding. !!! Vorlauf (recirculation) With a jug, collect some ~ 500mL of wort from the bottom of the tun and gently add to the top of the wort (a good idea is to rest a plastic lid on the top of the mash, and pour onto the lid). Alternatively you can drain wort from the outflow tract into the jug. Do this 4 to 5 times, until the wort is *no longer cloudy*. !!! Sparging: first runoff Top up with extra water (Vx). Now open the spigot and completely drain the wort into the kettle. (At this point put the kettle on a low heat.) !!! Sparging: second runoff Pour desired runoff volume (Vs) gently into mash. Wait 5 minutes, then vorlauf again, then run all liquid into the kettle. Turn the kettle heat on full. !! Boiling Bring to a rolling boil (be careful if covering, as can boil over like milk). Once boiling, uncover (maybe part-cover if small volume in a large kettle, to avoid excess evaporation). Skim off any "scum" on the surface. Add bittering hops at this point. Boil for 1 hour. During this time rehydrate the yeast if you wish. 15-30 minutes before the end, add the finishing hops. Dunk the immersion chiller into the boiling wort to sterilise it. !! Chilling Reduce the temperature of the wort rapidly to < 30C, using an immersion chiller etc. !! Fermenting Pour the wort into the fermenter. Measure the SG. Add the yeast. !! All grain try 16/1/2011 1kg "english pale ale" 2-row malted barley 1/2 oz NZ fuggle hops (7.2% alpha) Aimed for fermentable volume 5L, therefore pre-boil volume 6.66L (rounded to 7) strike water 2.8L added 1.7L prior to first runoff (to make up to 3.5L = half of pre-boil volume) after runoff 1, added further 3.5L and did runoff 2 a few hop pellets added pre boil, about 2/3 added upon reaching rolling boil (bittering), the rest added 10min before end of boil (finishing hops). dry ale yeast. Possible problems: - Mill may have crushed grains too finely - use mortar & pestle next time. Vorlauf liquid never really ran clear, maybe for this reason. - Mash temp drifted down to 62-63C for at least half the mash time. Maybe preheat the tun with hot water next time. - Added water to try and raise mash temp, but did not keep track of how much - Because the volume was low, too much of the wort evaporated during the boil (more than half), leaving only about 2.5L wort. Next time need to aim for higher pre-boil volume, or keep kettle half-covered during boil. !! All grain try #2 6/3/2011 1kg crystal malt 1.5kg english pale ale malt 2oz NZ fuggle hops Aimed for pre-boil volume 15L (maximum capacity of kettle) giving fermentable volume 11.25L Room temp 22C strike water 2.5kg x 2.7 = 6.75L at 83.3 C top up volume prior to first sparge = 7.5 - (6.75 - 2.5 - 0.3) = 3.95L after runoff 1, added further 7.5L same hop regimen and yeast as try #1 Used Victoria cast-iron mill to crush grains - worked well with a "spacer" to hold the teeth apart. Tun held temperature very well with larger volume - no need to add extra warmed water. Problems: - Kettle only holds 15L. Actually need a bit more because of water retained by grain - boil a full teakettle as well next time and allow to cool. - Only had about 9L Vf at the end - luckily had some pre-boiled water in kettle which I added. - No point measuring SG prior to boiling. Next time sterilise hydrometer and measure SG of the wort when cooled after boiling. culture Category:Product